1. Field of the Invention
This invention relates to a rotary machine that can be implemented as a compressor, pump, motor or combustion engine. This machine is mainly intended for use as an internal combustion engine.
2. Description of the Prior Art
Most internal combustion engines nowadays use reciprocating pistons. This design has severe inherent limitations: pressure and torque arm out of phase, high “inertial” forces between components due to acceleration/deceleration of pistons and change of trajectory of connecting rods, and expansion ratio tied to the compression ratio. Such limitations reduce performance, increase friction and wear, and reduce energy efficiency.
Many rotary designs have been proposed to overcome the inherent limitations of reciprocating engines. Although relegated to niche markets, the Wankel engine has probably been the most successful in commercial terms. Technically speaking, the Wankel engine has not completely solved old problems like friction and wear, and has problems of its own, especially low torque and troublesome sealing.
My invention is more related to toroidal engines, recent examples of which are found in U.S. Pat. No. 5,645,027 (Esmailzadeh); U.S. Pat. No. 6,276,329 (Archer); and U.S. Pat. No. 6,546,908 (Pekau).
Toroidal engines use pistons revolving in a toroidal chamber intersected by walls or valves. Generally speaking, compression is achieved by advancing the pistons against said walls/valves while deviating the compressed fluid to a separate chamber. At the end of the compression stroke, the intersecting wall/valve briefly retracts/opens to allow the piston pass by/through. In the meantime, combustion is started in the separate chamber. Combustion gases are then released behind the piston.
A key problem in prior art toroidal engines is the loss of compressed fluid during the opening and closing of the walls/valves. Such loss has an important toll on power output and energy efficiency, as it reduces the fuel-burning capacity of the engine, and at the same time increases the pumping power requirements for the compression and exhaust strokes.
Recent designs, disclosed in the already mentioned patents to Archer and to Pekau, have seemingly reduced compression losses to manageable levels. Archer's approach consists of very short pistons and an intersecting valve made of two counter-rotating discs. Pekau has instead modified the shape of the pistons in order to better match the intersecting valve, which is a single rotating disc.
The starting point of my approach has been to develop a simple method for “seamlessly” traversing one body through another moving in an intercepting trajectory. The result is the “blade-thru-slot” (BTS) concept. The application of this concept in a rotary machine leads to blades that orbit circularly inside a chamber and traverse intersecting planar valves through small slots. This approach virtually eliminates compression losses in a mechanically simple way; the slots are not only small in area but also remain “plugged” by the traversing blades while said slots are inside the chamber.
Although the Archer and Pekau engines have lower compression losses than previous toroidal designs, reduced fuel-burning capacity and excessive pumping power requirements are still present. Design limitations do no allow for positive removal of exhaust gases; instead, these remain in the toroidal chamber, between the revolving pistons, and are carried along until they get mixed with the intake charge. Similarly, there is no positive intake of air; an external charger is required to provide fresh air for the compression stroke. Consequences of these limitations are reduced intake of fresh air, excessive amount of exhaust gases in the intake charge, increased pumping losses, and ultimately lower power output.
The BTS engine provides complete removal of exhaust gases from the chamber, and positive intake of air, thus no external charger is required. This comprehensive “breathing” allows the BTS engine to achieve its full power potential.
Generally speaking, the BTS engine has the following advantages over prior art rotary engines: mechanical simplicity, very low friction (as no contact sealing is used), internal lubrication not needed, reduced pumping losses, comprehensive breathing and increased power output.
The above discussion is by extension applicable to other implementations of the BTS machine. Regarding compressors and pumps, main advantages of the BTS machine over reciprocating piston machines are lower friction and wear, no internal lubrication required and reduced power demand. In the case of prior art rotary compressors and pumps, the BTS machine is generally superior in terms of mechanical simplicity, reduced internal friction and no internal lubrication. Regarding pneumatic motors and similar compressed-fluid motors, the general advantages of the BTS machine over conventional and prior art machines are again mechanical simplicity, reduced internal friction, and no internal lubrication.